1. Q: What is the fundamental specification of EN10297-2 X5CrNi18-10 tubes?
A:
Material Standard: Seamless precision tubes under EN10297-2, equivalent to AISI 304 austenitic stainless steel.
Key Characteristics:
Corrosion Resistance: Excellent in oxidizing environments (PREN ≥18).
Temperature Range: Suitable for -196°C to 800°C (intermittent).
Primary Applications:
Chemical Processing: Heat exchangers, reactor piping.
Food/Beverage: Sanitary tubing, fermentation tanks.
2. Q: What mechanical properties are required by the standard?
A:
As-Annealed Condition:
Tensile Strength: 500–700 MPa.
Yield Strength (Rp0.2): ≥190 MPa.
Elongation (A₅): ≥45% (superior formability).
Hardness: ≤210 HB.
Cryogenic Performance: Impact toughness ≥100 J at -196°C.
3. Q: How does the alloy composition (18% Cr, 10% Ni) influence performance?
A:
Cr (17.5–19.5%): Forms Cr₂O₃ passive layer for corrosion protection.
Ni (8.0–10.5%): Stabilizes austenite phase, enhancing ductility and cryogenic toughness.
C (≤0.07%): Higher than 304L (X2CrNi18-9), offering better strength but requiring post-weld annealing for critical applications.
4. Q: What are the key quality control measures?
A:
Testing:
Corrosion Tests: ASTM A262 Practice E (intergranular).
NDT: Eddy current (EN 10246-3) for surface defects.
Certifications:
EN 10204 3.1 with material traceability.
FDA CFR 21 for food contact compliance.
5. Q: What are the welding and post-treatment guidelines?
A:
Welding: Use AWS ER308 filler with Ar+2% O₂ shielding gas.
Post-Weld: Anneal at 1010–1120°C for sensitized zones (if C >0.03%).
Critical Note: Avoid sulfur-rich environments to prevent hot cracking.
